Dislocation Substructure Contributions to the Tonal Qualities of the Caribbean Steel Drum - A TEM Study

Abstract

Deformation substructures, especially dislocations, play an important role in the fabrication of the Caribbean steel drum and experimental evidence also suggests dislocations play a crucial role in the harmonic tuning and related musical qualities as well. In this study, we have examined and compared the dislocation substructures in high-quality, low-carbon (0.04-0.06 weight percent carbon) steel drum heads as manufactured, and sections cut from variously deformed (10% to 50% reduction) drum head sections, including those patterned with musical notes and heat treated; utilizing TEM.We have recently shown that the requisite heating of a steel drum over a narrow temperature range (200 to 500°C) prior to tuning actually involves strain aging. Fundamentally, strain aging in steels has been explained by dislocation theory, but as far as we know, no experimental proof exists. This study also attempts to examine the more fundamental issues in strain aging, especially as it applies in the development of a high-quality, musical steel drum instrument.